Switzerland is a very interesting country to be learning a new language. Although the country is tiny there are four national languages: German, French, Italian and Rhaeto-Romanic. But be aware: In the German-speaking parts people actually speak a dialect of German, the Schwiizerdütsch – depending of the area you are in, the dialect also varies a lot. So make sure to have an impression of how it sounds. This video might help you with that.
For every language there is a respective level with certificate. A European grading system is being applied. In this system there are six different levels: A1-A2 (basic user), B1-B2 (independent user), C1-C2 (proficient user). Check this table (PDF) for more detailed information on these levels.
Recognized language certificates vary from language to language. Find the one that suits you:
German: Goethe Zertifikat
You can do the course individually or in a group. This decision of course influences the price, a group class is cheaper than having an individual course. The course organizers often organize a whole package, which includes accommodation in a shared flat or staying with other pupils in a hotel.
If you’d like to learn the language in a social context and get to know a Swiss person you could try to do a language tandem. You can find a partner in the data bank of Sprachtandem. You have to register, which is for free. Required data is i.a. year of birth, name and mail address (which is not visible for people visiting the page). After that you are able to contact the people who also signed up for the language tandem.